Hybrid TFC RO membranes with non-metallic additives

ABSTRACT

A process for preparing a reverse osmosis membrane that includes: (A) providing a polyamine, a polyfunctional acid halide, and a flux increasing additive having the formula Z + B − , where Z +  is an easily dissociable cation and B −  is a beta-diketonate; (B) combining the polyamine, polyfunctional acid halide, and flux increasing additive on the surface of a porous support membrane; and (C) interfacially polymerizing the polyamine and the polyfunctional acid halide, and flux increasing additive on the surface of the porous support membrane to form a reverse osmosis membrane comprising (i) the porous support membrane and (ii) a discrimination layer comprising a polyamide. The reverse osmosis membrane is characterized by a flux that is greater than the flux of the same membrane prepared in the absence of the flux increasing additive.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/293,744 filed Nov. 10, 2011, which claims priority to U.S.Provisional Application Ser. No. 61/412,184 filed Nov. 10, 2010, thecontents of which are hereby incorporated by reference in theirentirety.

TECHNICAL FIELD

This invention is related to discrimination membranes for use in reverseosmosis and forward osmosis processes, e.g., for purifying water.

BACKGROUND

Reverse osmosis membranes made by interfacial polymerization of amonomer in a nonpolar (e.g., organic) phase together with a monomer in apolar (e.g., aqueous) phase on a porous support membrane are known asTFC membranes and are used where flux and substantial rejectioncharacteristics are required, for example in the purification of water.Various materials have been added to TFC membranes in the hopes ofincreasing flux without reducing rejection characteristics and have metwith limited success. In addition, such membranes are subject to foulingresulting in reduced flux as contaminants, for example from the brackishor seawater to be purified, are believed to build up on the surface ofthe discrimination layer of the TFC membrane.

SUMMARY

A process for preparing a reverse osmosis membrane is described thatincludes: (A) providing a polyamine, a polyfunctional acid halide, and aflux increasing additive having the formula Z⁺B⁻, where Z⁺ is an easilydissociable cation and B⁻ is a beta-diketonate; (B) combining thepolyamine, polyfunctional acid halide, and flux increasing additive onthe surface of a porous support membrane; and (C) interfaciallypolymerizing the polyamine and the polyfunctional acid halide, and fluxincreasing additive on the surface of the porous support membrane toform a reverse osmosis membrane comprising (i) the porous supportmembrane and (ii) a discrimination layer comprising a polyamide. Thereverse osmosis membrane is characterized by a flux that is greater thanthe flux of the same membrane prepared in the absence of the fluxincreasing additive.

The polyamine may be selected from the group consisting ofdiaminobenzene, triaminobenzene, m-phenylene diamine, p-phenylenediamine, 1,3,5-diaminobenzoic acid, 2,4-diaminotoluene,2,4-diaminoanisole, xylylene diamine, ethylenediamine, propylenediamine,piperazine, and tris(2-aminoethyl)amine. The polyfunctional acid halideis selected from the group consisting of trimesoyl chloride, trimelliticacid chloride, isophthaloyl chloride, and terephthaloyl chloride.

In some embodiments, the polyamine, polyfunctional acid halide, and fluxincreasing additive may be combined with nanoparticles (e.g., zeolitesor carbon nanotubes). Interfacial polymerization then yields a reverseosmosis membrane that includes (i) the porous support membrane and (ii)a discrimination layer comprising a polyamide and the nanoparticles. Theporous support membrane may also include nanoparticles. In otherembodiments, the polyamine, polyfunctional acid halide, and fluxincreasing additive may be combined with mono-hydrolyzed trimesoylchloride prior to the interfacial polymerization.

In some embodiments, Z⁺ has the formula R¹R²R³R⁴N⁺, where R¹, R², R³,and R⁴, independently, are H, a C₁-C₆ hydrocarbyl group, a benzyl group,or a phenyl group. For example, in some embodiments, R¹, R², R³, and R⁴are ethyl groups, while in other embodiments, each R¹, R², and R³ groupis an ethyl group, and R⁴ is H.

B⁻ may have the formula:

-   where X and Y, independently, are H, a C₁-C₆ hydrocarbyl group, a    benzyl group, a phenyl group, —OR⁵, or NR⁶R⁷, each optionally    substituted with fluorine, and R⁵, R⁶, and R⁷, independently, are H,    a C₁-C₆ hydrocarbyl group, a benzyl group or a phenyl group. For    example, X and Y may be methyl groups, or X and Y may be    trifluoromethyl group.

Reverse osmosis membranes prepared according to this process may becapable of exhibiting a flux of at least 30 gfd, determined by exposingthe membrane to deionized water containing 32,000 ppm NaCl at atemperature of 25° C. and a pressure of 800 psi. the membranes may alsobe capable of exhibiting a salt rejection of at least 99.5%, determinedby exposing the membrane to deionized water containing 32,000 ppm NaClat a temperature of 25° C. and a pressure of 800 psi. The membranes maybe used to purify brackish water or seawater.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram of hybrid TFC membrane 10 during fabricationin which aqueous phase 14 including β-carbonyl additive 17, which may bepositioned on support 12, which may be strengthened by fabric 20,contacted by organic phase 14 which may include nanoparticle additives16 to create a thin film TFC membrane by interfacial polymerization(IFP).

FIG. 2 is a block diagram of hybrid TFC membrane 10 during operation inwhich feed stream 29 is applied to discrimination membrane 24—formed byIFP in the presence of a β-carbonyl additive 17 and/or nanoparticleadditives 16—through which purified water 34 permeates while salts andother contaminants are rejected.

FIG. 3 is a graph of the test results for 0.11 wt % and 0.26 wt %Et₃NH(F₆acac)₂ additive 17 with error bars indicating +/− standarddeviation representing the numerical test results shown in Table 1.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

A TFC membrane may be advantageously formed by interfacialpolymerization (IFP) between an organic phase which may optionallycontain nanoparticle additives and an aqueous phase containing aβ-carbonyl anion, released from a β-carbonyl additive, such astriethylammonium hexafluoro-acetylacetonate. In general, the β-carbonyladditive is in the form of Z⁺B⁻ where Z may be H⁺ or Z may be R¹R²R³R⁴N⁺where R¹R²R³R⁴ may be independently —H, —C₁-C₆ hydrocarbyl, -benzyl or-phenyl. For example, in some embodiments, R¹, R², R³, and R⁴ are ethylgroups, while in other embodiments, each R¹, R², and R³ group is anethyl group, and R⁴ is H.

B may be:

where Y and X may be independently —H, —C₁-C₆-hydrocarbyl, -benzyl,-phenyl, —OR⁵, or —R⁶R⁷, each optionally substituted by fluorine,wherein R⁵, R⁶, and R⁷ are independently —H, —C₁-C₆-hydrocarbyl, -benzylor -phenyl. In another preferred embodiment, X and Y may be CH₃ so thatB may be the β-dicarbonyl compound acetylacetone, optionally substitutedwith fluorine. B⁻ may be in a from having a single hydrogen atom at thecentral carbon, such as:

Z⁺B⁻ is easily dissociated in the aqueous phase solution.

B⁻ is preferably added in an amount that improves the permeability orflux of said reverse osmosis membrane and/or which maintains the saltrejection at a level greater than that of a control membrane madewithout additive. For example, the flux improvement preferably is on theorder of at least 20%, at least 35% and preferably at least 50%. Thesalt rejection preferably is at a level of at least 99% and preferablyat least 99.5%. The flux is preferably at least 27 gfd, more preferablyat least 30 gfd, and most preferably on the order of about at least 35gfd, while the salt rejection is on the order of about at least 99% orpreferable on the order of about 99.5%.

In addition to triethylamine, several other bases may be used to formthe β-diketonate salt. For instance, other alkyl or substituted alkylgroups may be present on the nitrogen, and the alkyl group may be eitherall the same, may be different. In addition to tri-substituted amines,ammonia, primary or secondary amines may be used. Quaternary ammoniumhydroxide solutions may also be used to prepare quaternary salts. Othernitrogenous bases may also be used including aniline, or aromaticsubstituted nitrogens, and heterocycles such as piperazine, pyridine, orimidazole.

Effective β-diketonates include 5-carbon or larger carbon frameworkcompounds where ketones are present on either side of a protoncontaining carbon atom. Atoms and substitutents may be presentthroughout the compound. Other electron withdrawing substituents such asfluorine can more preferably be present adjacent to the ketones to aidin the formation of the enolate compound.

FIGS. 1 and 2 describe a representative process for preparing a reverseosmosis membrane by IFP using a Z⁺B⁻ flux enhancing additive. Thediscrimination layer of the membrane illustrated in FIGS. 1 and 2 alsocontains nanoparticles 16; the resulting TFC membrane is referred to asa “hybrid TFC” membrane. Such nanoparticles, however, are optional.

In general, TFC membrane 10 may be synthesized using an interfacialpolymerization process on a porous support, such as support membrane 12.Conventionally, two immiscible solvents are used, one in aqueous phase14 and the other in organic phase 18, so that a monomer in one solventreacts with a monomer in the other solvent. The interfacialpolymerization reaction occurs at the interface between the twosolutions when aqueous phase 14 and organic phase 18 are brought intocontact with each other, to form a dense polymer matrixlayer—discrimination layer 24—on the surface of support membrane 12.

The polymerization reactions are very fast and relatively high molecularweights for the resultant polymer matrix are obtained. Once formed, thedense polymer matrix—which becomes discrimination layer 24—canadvantageously act as a barrier to inhibit ongoing contact between thereactants in aqueous and organic phases 14 and 18 to slow the ongoingpolymerization reaction. As a result, discrimination layer 24 is formedas a selective dense layer which is typically very thin and permeable towater, but relatively impermeable to dissolved, dispersed, or suspendedsolids, such as salts to be removed from sea or brackish water toproduce purified water. Resultant membrane 10 is conventionallydescribed as a thin film composite (TFC) membrane.

The first monomer can be a dinucleophilic or a polynucleophilic monomerand the second monomer can be a dielectrophilic or a polyelectrophilicmonomer. That is, each monomer can have two or more reactive (e.g.,nucleophilic or electrophilic) groups. Both nucleophiles andelectrophiles are well known in the art, and one of ordinary skill inthe art can select suitable monomers for this use. The first and secondmonomers are conventionally selected to react—when aqueous and organicphases 14 and 18 are brought into contact—by undergoing interfacialpolymerization to form a three-dimensional polymer network, often calleda polymer matrix.

The first and second monomers can also be chosen to be capable ofundergoing a polymerization reaction when aqueous and organic phases 14and 18 brought into contact to form a polymer product that is capable ofsubsequent crosslinking by, for example, exposure to heat, light,radiation, or a chemical crosslinking agent.

Regarding aqueous phase 14, the first monomer can be selected to besoluble in a polar liquid, preferably water, to form a polar mixture,referred to herein as aqueous phase 14. Generally, the difunctional orpolyfunctional nucleophilic monomer can have primary or secondary aminogroups and can be aromatic (e.g., a diaminobenzene, a triaminobenzene,m-phenylenediamine, p-phenylenediamine, 1,3,5-triaminobenzene,1,3,4-triaminobenzene, 3,5-diaminobenzoic acid, 2,4-diaminotoluene,2,4-diaminoanisole, and xylylene diamine) or aliphatic (e.g.,ethylenediamine, propylene diamine, piperazine, andtris(2-diaminoethyl)amine).

Examples of suitable amine species include primary aromatic amineshaving two or three amino groups, for example m-phenylenediamine, andsecondary aliphatic amines having two amino groups, for examplepiperazine. The amine can typically be applied to microporous support 12as a solution in a polar liquid, for example water. The resulting polarmixture typically includes in the range from about 1 to about 6 wt. %amine, preferably in the range of about 2 to about 4.0 wt. %, amine andmost preferably about 3.0 wt. % amine. The polar mixture need not beaqueous, but the polar liquid should be immiscible with the apolarliquid. Although water is a preferred solvent, non-aqueous polarsolvents can be utilized, such as acetonitrile and dimethylformamide(DMF) for aqueous phase 14.

Phase 14 can be called a polar phase or an aqueous phase because suchmixtures typically use water as the polar solvent. We believe mostpractitioners in this art refer to phase 14 as the aqueous phase. Toavoid any confusion, that convention will be followed herein so that theterm “aqueous phase” 14 is intended to refer to all polar phase liquids,e.g. whether or not the polar liquid is water.

During interfacial polymerization, aqueous phase 14 may include one ofthe reactants, additive(s) such as nanostructured materials, e.g.,nanoparticle additives 16, as well as processing aids such assurfactants, drying agents, catalysts, co-reactants, co-solvents, etc.The polar mixture, aqueous phase 14, is typically applied to microporoussupport membrane 12 by dipping, immersing, slot die coating, spraycoating, gravure coating or other well known techniques. Once coated onporous support membrane 12, excess polar mixture can be optionallyremoved by evaporation, drainage, air knife, rubber wiper blade, niproller, sponge, or other devices or processes.

For monomers having sufficient vapor pressure, the monomer can beoptionally delivered by vapor deposition from a vapor phase, or by heat,to support membrane 12.

Regarding organic phase 18, the second monomer can be selected to bemiscible with an apolar (organic) liquid, the mixture of which is shownin the figures as organic phase 18. Using the same convention discussedabove with regard to aqueous phase 14, the typically used term “organicphase” is intended to refer to any appropriate nonpolar mixture, e.g.organic phase 18.

The electrophilic monomer can be aromatic in nature and can contain twoor more, for example three, electrophilic groups per molecule. Forexample, the second monomer can be a trimesoyl halide. For the case ofacyl halide electrophilic monomers, acyl chlorides are generally moresuitable than the corresponding bromides or iodides because of therelatively lower cost and greater availability.

Suitable polyfunctional acyl halogens include trimesoyl chloride (TMC),trimellitic acid chloride, isophthaloyl chloride, terephthaloyl chlorideand similar compounds or blends of suitable acyl halides. As a furtherexample, the second monomer can be a phthaloyl halide.

The polyfunctional acyl halide—e.g., TMC—can be dissolved in the apolarorganic liquid, e.g., organic phase 18, in a range of, for example, fromabout 0.09 to about 1.0 wt. %, preferably from about 0.17 to about 0.3wt. %. and most preferably in the range of about 0.3 wt. % TMC. Suitableapolar liquids are capable of dissolving the electrophilic monomers(e.g. polyfunctional acyl halides) and which are immiscible with a polarliquid (e.g., water) in aqueous phase 14. In particular, suitable apolarliquids preferably include those which do not pose a threat to the ozonelayer and yet are sufficiently safe in terms of their flashpoints andflammability to undergo routine processing without having to undertakeextreme precautions.

These include C₅-C₇ hydrocarbons and higher boiling hydrocarbons, i.e.,those with boiling points greater than about 90° C., such as C₈-C₂₄hydrocarbons and mixtures thereof, which have more suitable flashpointsthan their C₅-C₇ counterparts, but are less volatile. The apolarmixture—organic phase 18—can typically be applied to contact aqueousphase 14 on microporous support membrane 12 by dipping, immersing, slotdie coating, spray coating, gravure coating or other well knowntechniques. Any excess apolar liquid can be removed by evaporation ormechanical removal. It is often convenient to remove the apolar liquidby evaporation at elevated temperatures, for instance in a drying oven.Preferred ovens include flotation ovens, IR dryers, and laboratoryconvection or gravity ovens. Control of both web temperature andevaporation rate may be used to alter structure and performance.

Referring now to FIGS. 1 and 2, a hybrid TFC membrane is shown infabrication and then again in operation. In fabrication, aqueous phase14 is applied to support membrane 12, which preferably rests on fabric20. Support membrane 12 is typically a polymeric microporous supportmembrane, which in turn is often supported by non-woven or wovenfabrics, such as fabric 20, for mechanical strength. Fabric 20 ispreferably a polyester fabric having a basis weight of 60-120 grams permeter or gsm, and a thickness of 50-200 microns. Support membrane 12 maybe made from polysulfone or other suitably porous membranes, such aspolyethersulfone, poly(ether sulfone ketone), poly(ether ethyl ketone),poly(phthalazinone ether sulfone ketone), polyacrylonitrile,polypropylene, cellulose acetate, cellulose diacetate, or cellulosetriacetate. Support membrane 12 may be 25-100 nm in thickness,preferably about 35 nm to about 75 nm and most preferably about 50 nm inthickness and may have the smallest pores located very near the uppersurface. Porosity at the surface may be low, for instance from 5-15% ofthe total surface area.

Aqueous phase 14 contains a β-dicarbonyl additive 17, such asEt₃NH(F₆acac)₂. It is believed that Et₃NH(F₆acac)₂ is easily dissociatedinto an Et₃NH⁺ cation Z⁺ and an (F₆acac)₂ ⁻ anion in aqueous phase 14.Additive 17, as shown in FIG. 1, has the formula Z⁺B⁻, wherein B is anacetylacetonate moiety defined above and Z is an easily dissociatedmoiety such as ammonium ion defined above, which improves thepermeability of the resulting reverse osmosis membrane 10 relative to acontrol membrane made without additive 17. Without wishing to be boundby theory, it is thought that additive 17 interferes with full crosslinking of the polyfunctional acid halide (e.g., trimesoyl chloride) andpolyamine (e.g., methylene phenylene diamine) compounds during IFP.

Aqueous phase 14 is contacted with organic phase 18, which may containanother additive such as nanoparticles 16, to create discriminationmembrane 24 by IFP as illustrated in FIG. 2. Examples of nanoparticles,including nanostructured materials such as carbon nanotubes and metalorganic frameworks (MOF), that may be combined with the polyamine,polyfunctional acid halide, and beta-diketonate flux increasingadditive, include:

Linde Type A (LTA) zeolites available freeze dried, 100 nm diameter fromNanoscape AG, Am Klopferspitz 19, D-82152 Planegg, Germany;

Linde Type Y (FAU) zeolites as described in MICROPOROUS AND MESOPOROUSMATERIALS Volume: 59 Issue: 1 Pages: 13-28 Published: Apr. 18, 2003 byHolmberg B A, Wang H T, Norbeck J M, Yan Y S;

Zeolite Beta as described in MICROPOROUS AND MESOPOROUS MATERIALSVolume: 25 Issue: 1-3 Pages: 59-74 Published: Dec. 9, 1998 by Camblor MA, Corma A, Valencia S); and

Cu MOF: A metal organic framework complex prepared from Cu and trimesicacid as described in Science 283, 1148 (1999); Stephen S.-Y. Chui, etal. “[Cu3(TMA)2(H2O)3]n A Chemically Functionalizable NanoporousMaterial”.

Either during IFP, or once the polymer matrix is formed, the anionbelieved to be present in this solution may interfere with the formationof covalent crosslinking Instead, ionic cross linkages between thehydrolyzed acyl halide groups and the terminal amines are formed. Suchionic cross-links, compared to the largely covalently crosslinkedcontrols, promote increased water uptake and flux. At the same time,rejection may be maintained by virtue of these ionic crosslinks betweenthe charged groups. Relative to ionic interactions in solution, theseionic crosslinks are stabilized by the rigidity of the polymer networkkeeping the two charged centers close to each other. The ionic crosslinkmay also allow a slight expansion of the matrix relative to a covalentbond, thereby increasing water uptake.

EXAMPLES

The general procedure for the preparation of a flat cell test membranewas to prepare aqueous and organic phases, add the desired additives toone or both of these phases, apply the aqueous phase to a wetpolysulfone membrane support on a glass plate, and then apply theorganic phase to the aqueous phase on the membrane support as describedin more detail immediately below. Control membranes were made in asimilar way, except without the additive(s). All performance data unlessotherwise noted was obtained from flat sheet testing on NaCl (32,000ppm. 53 mS/cm) in tap water tested at 25° C. and 800 psi. Flow andrejection were measured after 1 hour of running.

Aqueous Phase 14:

An aqueous solution of MPD, 4.5 wt % of triethylammoniumcamphorsulfonate (TEACSA), and 0.06 wt % sodium lauryl sulfate (SLS) inDI water, and 0, 0.11, or 0.26 wt. % Et₃NH(F₆acac)₂ was prepared.Et₃NH(F₆acac)₂ was synthesized in-house and used without furtherpurification. The procedure used was:

-   -   Add 25 g ampoule hexafluoroacetylacetone (98%, Aldrich 238309,        Lot MKBB2482) to 100 ml n-hexane that was stored over molecular        sieves (96%, Acros 364370010, Lot 0930139) with stirring.    -   Add 12.14 g triethylamine (Fluka 90342, Lot 1389546) added with        stirring.    -   2 phases formed with bottom being a deep yellow color.    -   After ca. 30 minutes, top layer decanted off and yellow phase        stored overnight.    -   Small amount of less dense phase collected overnight on top of        the yellow phase and was removed the next day.        Organic Phase 18:        An Isopar G® solution with 0.3 wt. % TMC and 4 wt. % mesitylene        was also prepared and sonicated for up to 60 minutes. Isopar is        a trademark of Exxon Corp.        Support Membrane 12:        A piece of wet polysulfone support was placed flat on a clean        glass plate. An acrylic frame was then placed onto the membrane        surface, leaving an area for the interfacial polymerization        reaction to take place.        Discrimination Membrane 24:        Approximately 50 mL of the aqueous MPD solution was poured onto        the framed membrane surface and remained for up to 2 min. The        solution was drained by tilting the frame till no solution        dripped from the frame.    -   i) The frame was taken off, and was left horizontally for 1        minute. The membrane was then clamped with the glass plate in        four corners. An air knife was used to finish drying the        membrane surface. The membrane was reframed using another clean        and dry acrylic frame and kept horizontally for 1 min.    -   ii) Approximately 50 mL of the organic solution was poured onto        the framed membrane surface and remained for 2 minutes. The        solution was drained by tilting the frame (vertically) till no        solution dripped from the frame. The acrylic frame was removed,        and the membrane was kept horizontally for 1 minute. The        membrane was then dried at 95° C. for 6 minutes.

Two TFC membranes were synthesized and tested for each condition.

Referring now to FIG. 3, the results of the testing above discussedabove for 0.11 wt % and 0.26 wt % Et₃NH(F₆acac)₂ additive 17 are shownwith error bars indicating +/− standard deviation. These tests show thatboth flux and rejection are affected by the concentration ofEt₃NH(F₆acac)₂ in a similar manner as they are affected by the additionof certain other additives 17 such as alkaline earth additives. Table 1below provides the test numerical results. Example 1, which contained nobeta-diketonate additive, was used as a control.

TABLE 1 Membranes with Et₃NH(F₆acac)₂ additives 17 x. # MPD TMC RatioAqueous 14 FLUX GFD REJ. 1 4% 0.3% 13.3 21.8 99.5% 2 4% 0.3% 13.3 0.11wt % 26.9 99.53% Et₃NH(F₆acac)₂ 3 4% 0.3% 13.3 0.26 wt % 29.6 99.27%Et₃NH(F₆acac)₂ 4 4% 0.3% 13.3 0.13 wt % 30 99.57% Et₃NH(F₆acac)₂ 5 4%0.3% 13.3 0.36 wt % 32 99.52% Et₃NH(F₆acac)₂ 6 4% 0.3% 13.3 0.13 wt % 3299.57% Et₄N (F₆acac)2 7 4% 0.3% 13.3 0.28 wt % 34 99.5% Et₄N (F₆acac)2 84% 0.3% 13.3 0.08 wt % 32 99.57% F₆acac 9 4% 0.3% 13.3 0.17 wt % 35.599.45% F₆acac

Without being restricted to this hypothesis, it is believed that themechanism of action of these β-diketonate salts may be a result of aninteraction or reaction with one or more of the acyl chloridefunctionalities present on the TMC in organic phase 18. β-diketonatecompounds and their enolate salts may react with acyl halides eitherthrough the carbon adjacent to both ketones, a substituted ketone, orthrough the oxygen forming an ester. These formed compounds may eitherparticipate directly in the film formation, may react with end groupspresent after the initial polymerization, or the formed compound itselfmay undergo further reactions leading the true effective agent. Theseformed compounds are believed to be particularly effective when producedin concert with the IFP reaction itself, perhaps due to a decreasedtendency to reduce molecular weight that may occur if the compound werepresent at the onset of the polymerization reaction. This may occur whenthe β-diketonate is brought into contact with TMC at the same time, orafter the amine reactant.

This reaction may occur either in aqueous phase 18 after a small amountof TMC partitions into aqueous phase 14, at the aqueous-organic phaseinterface, or in organic phase 18 after the substituted ammoniumβ-diketonate salt partitions into organic solution 18.

A number of embodiments of the invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the invention.Accordingly, other embodiments are within the scope of the followingclaims.

What is claimed is:
 1. A composition, comprising: a flux increasingadditive having the formula Z⁺B⁻, wherein Z⁺ is an easily dissociablecation selected from among H⁺ and R¹R²R³R⁴N⁺, where R¹, R², R³, and R⁴,each independently is H, a C₁-C₆ hydrocarbyl group, a benzyl group, or aphenyl group, and B⁻ is a beta-diketonate; an aqueous phase containing apolar liquid; and a difunctional or polyfunctional nucleophilic monomer.2. The composition of claim 1, wherein Z⁺ has the formula R¹R²R³R⁴N⁺,where R¹, R², R³, and R⁴, each independently is H, a C₁-C₆ hydrocarbylgroup, a benzyl group, or a phenyl group.
 3. The composition of claim 2,wherein R¹, R², R³, and R⁴ are ethyl groups.
 4. The composition of claim2, wherein R¹, R², and R³ each is an ethyl group, and R⁴ is H.
 5. Thecomposition of claim 1, wherein B⁻ has the formula:

where X and Y, independently, are H, a C₁-C₆ hydrocarbyl group, a benzylgroup, a phenyl group, —OR⁵, or NR⁶R⁷, each optionally substituted withfluorine, and R⁵, R⁶, and R⁷, each independently, is H, a C₁-C₆hydrocarbyl group, a benzyl group or a phenyl group.
 6. The compositionof claim 5, wherein X and Y each independently is a C₁-C₆ hydrocarbylgroup, a benzyl group, a phenyl group, —OR⁵, or NR⁶R⁷ each substitutedwith fluorine.
 7. The composition of claim 5, wherein X and Y are methylgroups.
 8. The composition of claim 5, wherein X and Y aretrifluoromethyl groups.
 9. The composition of claim 5, wherein X and Yare selected so that B⁻ has a 5-carbon or larger carbon framework. 10.The composition of claim 1, wherein the nucleophilic monomer is apolyamine selected from the group consisting of diaminobenzene,triaminobenzene, m-phenylene diamine, p-phenylene diamine,1,3,5-diaminobenzoic acid, 2-4-diaminotoluene, 2,4-diaminoanisole,xylylene diamine, ethylene diamine, propylene diamine, piperazine andtris(2-aminoethyl)amine.